HDMI Sink Port Power Management via VSYNC Edge Synchronization
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Solution Overview
Problem
Current HDMI technology experiences significant power consumption and delays when switching between HDMI ports due to HDPC encryption, requiring synchronization operations that prolong the time before video is displayed on the new port.
Innovation Solution
A power-saving method that uses reference signals to locate the VSYNC active edge in each frame, turning on power only during the corresponding power-on region for the second HDMI port, and obtaining HDCP information to enable immediate video display when switching ports, reducing power consumption and synchronization time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If all HDMI ports are kept on to synchronize HDMI lane signals in advance, then the switching speed between ports is improved, but the power consumption increases significantly
Solution Approach 1:
The patent applies preliminary action by keeping only the necessary HDMI ports synchronized and ready in advance, rather than all ports. The sink device identifies which source devices are likely to be switched to and pre-synchronizes those specific ports, reducing power consumption while maintaining fast switching capability when needed.
Solution Approach 2:
The patent implements dynamics by making the HDMI port power state adaptive rather than static. The sink device dynamically adjusts the power state of HDMI ports based on usage patterns, switching between powered-on and powered-off states, and pre-synchronizing only when a switch is anticipated, thus optimizing the balance between switching speed and power consumption.
2Reliability
If HDCP encryption is implemented, then digital content protection is improved, but the switching time between HDMI ports increases due to required synchronization operations
Solution Approach 1:
The patent applies preliminary action by performing HDCP synchronization operations in advance for anticipated port switches. The sink device pre-establishes HDCP handshakes with potential source devices before switching occurs, so that when the user actually switches ports, the content protection is already established and video can be displayed immediately without waiting for synchronization.
Solution Approach 2:
The patent implements skipping by bypassing the full HDCP synchronization sequence when it has been pre-completed. The system detects that HDCP handshaking has already occurred for the target port and skips the redundant synchronization steps, rushing directly to video display while maintaining content protection integrity.
3Use of energy by moving object
If HDMI ports are turned off to save power, then power consumption is reduced, but the video display is delayed when switching ports
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing HDMI lane signals and HDCP handshakes for ports that are kept in a low-power state. Before turning off power to an HDMI port, the system performs necessary synchronization operations in advance, so that when power is restored during switching, the port can immediately display video without significant delay.
Solution Approach 2:
The patent implements periodic action by cyclically managing HDMI port power states based on usage patterns. The system monitors which ports are actively used and which are dormant, periodically switching ports between powered-on and powered-off states, and pre-synchronizing dormant ports before they need to be activated, thus balancing power savings with minimal display delay.
Data Source
AI summary
A power-saving method for switching High Definition Multimedia Interface (HDMI) ports on a sink device is provided. The sink device has a first HDMI port initially being enabled for displaying and a second HDMI port being disabled for displaying. The power-saving method includes the steps of using the reference signals to locate the VSYNC active edge in each frame generated by a source device connected to the second HDMI port; turning on the power to the second HDMI port during a power-on region corresponding to the VSYNC active edge in each frame and turning off power otherwise; obtaining information related to a high bandwidth digital content protection (HDCP) in the power-on region; and displaying video data from the source device based on the HDCP information when enabling the second HDMI port connected to the source device.